Heat a small amount of water in a large stockpot over medium-low heat.
Add the green onions and sauté until softened.
Add the carrot, cauliflower, potatoes, water, and thyme. Cover the pot and bring to a boil. Once boiling, reduce to a simmer.
Let simmer for 20 minutes then add in the parsley and stir until wilted. Turn off the heat.
Puree the soup using a blender or handheld immersion blender. (Note: If using a regular blender, be careful. Ensure you leave a space for the steam to escape when blending a hot liquid.) Taste and adjust seasoning if needed.
Ladle into bowls and enjoy!